Conveyer-belt.



MAY 1906.

ILE?) ELPE. 15% 1905.

l UNITED sTATEs PATENT OFFICE.

GEORGE o. PLUMMEa OF rHILADELPHIA, PENNsYLvANiA.

vConvErfinder-2LT.

Specification of Letters Patent.

Patented May 22, 1906.

lApplication 'filed April 18, 1905. -Serial No, 256,23?.

. accompanying drawings, which form a part of this specification.

My invention relates to conveyer-belts for f use on troughing-rollers.

The object of the inventiony is to minimize the destructive effects arisin r from thebending of the belt along longit inal lines at the angles of divergence between the flat and turn-up portions of the belt and secure iiexlbility of the belt along these lines without at the same time resorting to any expedient that will thin or weaken these portions of the belt or render the belt a whole less firm and wear-resisting than is practically necesA sar n rly`o this end my invention consists of a belt made of two or` more comparatively. thin sheets of belting material secured together along .their longitudinal ycentral portions, but left independent of each other between'their middle parts and their edges.

Before setting forth more s ecifically the construction of my improved elt it may be well to briefly describe the present general s stem of troughing beltf conveyers or troughed-belt conveyors andthe4 cause and nature ofthe destructive wear to which their belts are exposed.

Belt conveyers in general consist, essentially, of two end pulleys around and between which an endless` belt is arranged to run. That part ofthe belt between the upper art-s of the two end pulleys may be calle( the upper run and 4that part between the lower parts of the pulleys the lowerrun The material Ito be handled is usually. placed on the upper run of the belt.. To cause the belt to assume a trough sha-pe, it is customary to cause the same to travel over idler-pulley sup Orts arranged in a trough shape.- A pre erred form of such idler-pulley supports consists of sets of idlers, each sct composed of a central flat pulley and two turn-up or inclined pulleys. The run carrying the load is the only part Of the belt that is supported on troughing-rollers, and which in consequence is troughed. Tokeep it from sagging unduly, the return run of the belt-that run which is notloaded-is usually supported at intervals'by flat rollers on which the belt lies flat. The end pulleys also are necessarily fiat, or approximately so. The normal form, therefore, of a conveyer-belt is flat. Therefore when a c'onveyer-belt is trou hed or bent into acurve shape distortion rom its normal transverse section takes place. Be.- ing bent or curved, the surface and parts adjacent thereto at the inside of the curve tend to become compressed, while the surface and partsadjacent thereto at the outside of the curve tend to become stretched. Extreme transverse ben ing or curvature of a belt of appreciable thickness will finally buckle the surface andadjacent parts along the inside of the curve and rupture and tear a art the surface and adjacentparts along t Outside. y

Belts are troughed in order that'they 'm ay; carry comparatively large loads without V.spilling the same, and as the angle or de ee of troughingwithin limits increases the elt carrying capacity increases. As the degree oftroughing increases so does the distortion and conse uent strain of a given belt. Also as the thic ness of a belt of a given material as heretofore constructed increases so also does its resistance to trou hing increase.

In order to impart su cient flexibility to the belt `along the lines of bending, different expedients have been resorted to, and troughed conveyer-belts in commercial use are ci ther made especially flexible as a whole lgo by making them of some soft yielding material or else the essential resistive substance of the belt along the lines of bending is made thinner than elsewhere. Belts thus constructedv attain the advantage of flexibility along the lines of bending at the sacrifice ofdurability. A belt to resist the wear or lo'adings of heavy and rough or abrasive material must berm and wear-resisting throughout, so that it may present a surface that may appreciably Wear away without being thereby rendered entirely useless, and to resist the blows of loading without being punctured it must have a good thickness throughout. .It is obvious that a belt made throughout of soft and yielding material will .not fill these v relurements. It is equally evident that a be t made thin in art will be weak in that part and that the ife of the belt as a Whole cannot exceed the life of its weakest part.

IIO

In my belt l attain the advantage of capacity for readily flexing and bending and at thel portance.

same time secure the advantages of a belt of firm and wear-resisting qualities and of the desir'ed thickness tln'oughout. Its preferred construction will be understood by reference to the accompanying drawings, in which-*- Figure l is a sectional view of the belt hewn supported on troughing idler-pulleys, the latter .heilig shown in side elevation. Fig. 2 is a sectional View of a modiiication. Fig. 3 is a sectional view of another modification. Fig. 4 is aplan view of' a short length t the belt of Fig, 1.

vReferring irst to the construction shown in Fig. 1, a a a are the troughing-pulleys. b b are two pulleys so placed as to prevent the belt from running too far over sidewise. The belt is composed of two leaves, sheets, or sections-an upper section c and a lower section d. Between the points e and f-that is, the longitudinal central portion of the belt-the two sections are secured together by means of rivets g and stitches h, extending through both sections. rIhs portion of the belt is therefore to all intents a single or unitary.

thick belt. Between the points e and f and the respective edges of the belt the two sections are in' a sense entirely independent inl that they are not secured together, while in another sense having no longitudinal movement in relation to each other they form together a combination-belt, and therefore retain all the advantages of a unitary belt of the required thickness and firmness. At the same time each section is at liberty' to bend independently along the longitudinal lines dictated by the arrangement of the troughing-idlers.

'lhc freedom with which the upper and lower sections of the belt can bend independently of each other is a feature of great im- A thin piece of material bends more readily than a thick piece. Theoretically and practically to all intents each half ofrny belt will be subjected to strains of only oncquartcr of the intensity ol those that the belt would be subjected to were both halves secured together7 so as to bend or ilex as one piece.

In F ig. l it will be noted that the edges of the upper half ol` the belt project materially beyond those. ol' the lower half. In reality the upper hall oll the belt is no widerthan the lower hall', and the displacement of the top edges with respect to thc lower merely illustrates the tendency there is to distortion between the parts when a belt is curved, as shown. Il the top part were secured to the lower, buckling in the top would tend to lake place, whereas my belt,permitting adjustment ol the parts by sliding, doesl away to a great extent with any such tendent-,iY to buckle.

llaving two thicknesses instead of only one at the points at which bending takes placai,'o|, in other words, having belt thiclc ness instead ot bel t thinness under the lo ad ing,

I supply power of resistance to belt wear both from friction. and trom impact of blows of material. Again, by attaining this thickness by the use ot two separate sheets of material instead of the use of a single sheet f' their combined thickness I can make each of my sheets of a tougher and more firm and wear-resisting material than can be used for a single sheet ol" double thickness and still can have a large percentage of flexibility in my favor.

As shown in Fig. 1, each section of the belt consists of three thicknesses or plies of canvas. i represents the stitches extending through the three plies of canvas constituting the upper section, and c represen ts the stitches extending through the three plies of canvas constituting the lower section. Thestitches i and lc, extending through the central portion of the belt between the points e and f, may, it desired, be omitted, so that this portion of the belt will then differ no wise from a single thick belt.

In the modification shown in Fig. 2 I omit the rivets q of F ig. 1 and rely entirely on the stitches h for securing the two sections of the belt together.

In the modification shown in. Fig. 3 I omit the stitches h of Fig. l and rely entirely on the rivets g for securing the two sections ol the belt together.

As shown in all three figures, the edges of the upper section are thickened in orderto provide resistance should the belt run over sidewise and contact with the guide-rollers l). The drawings show the thickening of the edges eil'eeted by means ot' an extra ply or plies of canvas inserted inside the outer plies ofthe belt.

My invention is not limited in its applica# tion to a belt ot stitched canvas construction. It maybe made of solid woven material, or of rubber, or of leather, or may be formed in any suitable way and of any suitable material; nor is my invention limited to the particular instruinentalities shown for securing the two sections together, as this may be donc by glue, cement, or otherwise; nor if the belt be made of canvas or of other material put together in plies is the number of thicknesses or plies of material a material feature; nor is it necessary that the two sections ol' belt shall be of the same thickness, as for special reasons it may be desirable to make one part thicker or heavier than the other; nor is it essential to the embodiment of my broad invention that one of the seetions should be thickenedalong its edges; nor is it necessary to the narrower embodivroo ment ol my invention that comprehends the by the particular expediknt shown and de scribed. u i

ISO

While I show a belt consisting of two sections r sheets, my invention would be equally embodied in a belt consisting of three or more sections or sheets.

I am aware that it has been proposed to 1pply a sheet of asbestos to the surface ofthe .of September 12,1899.

t, as in the Ridgway patent, No. 632,750, In the specification of that patent it is stated that the asbestos sheet may be riveted or otherwise attached tc the belt, and, in Figs. 3 and 4 of the drawings the sheet is apparently shown as lriveted-only between and not outside the lines of bendof the belt. This construction, however, .does not exhibit a belt embodying my invention, but at the most merely exhi its a belt not embodying my invention I and a removable protecting-sheet correlated .gestive of my improved belt.

in a way somewhat analogous to the relation 2O ling of each section is but one-quarter of that which would occur if the two sections were secured to each other throughout their width. In the Ridgway construction the buckling of the belt is no less than it would be if the vasbestos sheet were secured vto the belt throughout-the latter'swidth, the reason for this being that the asbestos sheet being of a loose fibrous texture offers no substantial resistance to the displacement of its particles, and therefore if secured throughout its width to the bel would not subject the belt to any buckling strain substantially greater than that to which it would be subjected if the asbestos sheet were entirely absent.

Having now fully described my invention, what I claim, and desire to protect byLetters Batent, is-

LA conveyerfbelt comprising a plurality of sheets secured together along their central portions and disconnected from, but contacting with, each other between their central portions and edges.

2. A convcyer-belt comprising three longitudinal portions, the central portion comprising a unitary or integral structure, while the two side portions consist of a plurality ol disconnected but contacting sheets lree to bend independently.

3. A iamveyer-lielt comprising a plurality ol' sheets secured.together along their central portions only and l'ree from each other outside their central portions.

4. A convey rielt comprising a longitudinal central portion composed ol` a plurality ol sheets restrained from moving relatively both longitudinally and laterally, and side portions each composed of a plurality of sheets restrained from relative longitudinal moves ment but capable of independent lateral movement.

5. A conveyer-belt comprising a plurality of super-posed sheets contacting throughout their width and restrained from independent movement longitudinally but capable of limited movement laterally relatively to each other.

6. A conveyer-belt comprising a plurality of sheets secured together along their central portions only.

7. A conveyer-belt comprising a plurality oi' sheets contacting throughout but secured together along a part only of their width.

8. A conveyenbelt coniprising a plurality' of superposed sheets having contacting side portions adapted when bent to slide laterally one upon the other.

9. A conveyer-belt comprising a -plurality of superposed sheets free and independent of each other only along the portions adjoining their longitudinal edges.

10. A convevenbelt comprising a central longitudinal portion comprising a unitary or integral structure, and side portions consisting of a plurality ol' sheets free to bend independently, the edges of one or more of the sheets being thickened.

11. A conveyer-belt comprising a plurality of sheets secured together along their centrai portions and free from each other between their central portions and edges, the edges of the upper sheet being thickened.l 12. A conveyer-belt comprising a plurality of sheets, and fastening means extending through all the sheets and securing them togetlier along their longitudinal central portions only.

plurality of sheets, each sheet composed of av plurality of thicknesses of canvas, stitches extending through the several thicknesses of each sheet across the entire width thereof, and .fastening means securing together the seyeratsheets along their longitudinal cent-ial portions only. y

In testimony ol' which invention I have hereunto set in v liand, at Philadelphia, on this 11th day of April, i905.

GEORGE (l. lliUltlltllllt.

Witnesses:

M. M. llAMii/ioN. 'l`-|ionNi,i-1Y li. Woon, 

